


I Scream, You Scream

by meadowsandapathy



Category: Undertale (Video Game)
Genre: Ecto-Penis (Undertale), F/M, Multi, Other, Plot What Plot/Porn Without Plot, Public Sex, Reader can be interpreted as gender neutral, Semi-Public Sex, Shameless Smut, Size Kink, Smut, Teacher-Student Relationship, however they do have dfab descriptions, in fact, it happened, professor sans, tldr; you get fucked in class literally, ya sinners, yup
Language: English
Status: Completed
Published: 2016-09-23
Updated: 2016-09-23
Packaged: 2018-08-16 22:47:01
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 1,162
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/8120494
Author URL: https://archiveofourown.org/users/meadowsandapathy/pseuds/meadowsandapathy
Summary: Maybe it wasn't such a good idea to take his bet.After all, it's very difficult to keep quiet in the middle of class when he's fucking you so roughly.





	

**Author's Note:**

> S I N

You’re losing your mind wondering how he does this.

Teaching takes a hell of a lot of concentration – you know, because you tried getting a teaching minor. That didn’t last long. But anyway, somehow, Professor Sans has done the impossible. He’s managed to not only stay on track in his lesson for today…

…but he’s managed to do it while violently fucking you in your seat.

Of course, you know his ticks and quirks intimately; he really is off his usual game, his speech littered with more ‘uh’s and ‘umm’s than his other lessons, but other than that, there’s nothing off that anybody else could possibly catch. But _you_ see it. Ever so slightly, at the exact moment your neighbor’s watch flashes to count a second going by, Sans’ left pointer finger twitches.

And every time it twitches, the cock inside you rams itself into your heat.

And every time, _every_ single time, you have to try not to cry out in the middle of a two-hundred-and-fifty person lecture. All because of that stupid bet. ‘ _Hurr hurr_ , bet you can’t take my dick in public without screaming, _mleh mleh_ ,’ shut the fuck up past Sans. He has no idea how difficult it is to remain quiet when a pulsing cock continuously drives itself into you over and over, shoving against your walls without a care of who hears the dangerously loud and wet sounds. This – it’s been going on for the entire lecture.

In reality, it’s all your fault that you replied to his challenge with a taunting, ‘ _Bet you can’t teach while trying_.’

And here you are, biting your fist so hard that your seat neighbor looks like he’s considering calling you an ambulance. Okay, maybe not, but it’s a good distracting thought while Sans demonstrates the motion of a sound wave for the class. His finger slowly goes up and then comes back down, his cock dragging against every sensitive area it can reach on its way through. You’d congratulate yourself for your swallowed whimper, but he keeps repeating the motion, so you can’t really focus on celebrating yet.

You don’t even know what he’s saying; his eyes bore into you from his position at the front of the class, his finger _still_ making the motion (we get it! Sound is a wave!), and you know that his focus is all on you right now, even if he’s spouting his fancy physics jargon.

His smile twitches when your walls clench around his dick instinctively. Oh – so he _can_ feel this. He misses your smirk as he turns toward the board, a marker in his right hand. Oh god, his dick stops moving, you have the chance to do something remarkably stupid –

“so we can model sound like a wave. the lowest point is the trough and the h _hrrk –_!”

You huff a discreet laugh as you twist your hips in a manner that looks like you’re just shifting in your seat. The hairs on the back of your neck stand as your action sends your heat on a slow grind down his dick, and at the same time, you clench as hard as you can around his length. From your position in the middle of the lecture hall, you can barely perceive the slight twitch of Sans’ hips.

“—highest point is the crest. alright, welp, that’s it for today. help room hours are on wednesday before your first test.”

Your throat keens the slightest whine as his cock dissipates. You have to cross your legs so nobody passing your seat can see the prominent dark spot at the crux of your pants. Oh god, he didn’t even make you come, let alone make you scream! But that’s the least of your worries. The height of your worries right now is the fact that Sans is very quickly dismissing the students lined up to ask him questions.

You gather your things. Slowly. A few students dawdle, chatting about nothing, and you want them to leave so you can know if Sans is pissed or not. A bet is one thing, but he really is a professor who probably shouldn’t be interrupted by you grinding on his dick in the middle of class, and…

…you haven’t realized everyone has left until you hear the doors click shut, lock, and feel Sans’ hands tightly grab your hips. His body rests firmly against your back.

“ _that_? was unfair.”

“Would you call it a ‘dick move’?” You snicker, only stopping when his fingers enter your open mouth.

“no, i call _this_ a dick move.” And all of the sudden, he yanks down your pants and rams himself to the hilt inside of you. The fingers in your mouth do nothing to hinder the violent yelp that comes out of you, nor the drawn out moan wavering with each of his successive thrusts. Your hands desperately claw at the seat in front of you as it barely gives you purchase.

Whoops, it doesn’t give enough support, it seems. One thrust fills you so hard, so quickly, that your hands slip and your body arches over the seat. His dick can only fill you deeper from this position, your ass high in the air. His fingers are forced to leave your mouth, so they make home traveling down your exposed stomach and begin toying with your outer lips where his cock enters you rapidly.

“we both won the bet, i’d say,” he says as if he isn’t plowing you in the middle of an empty classroom. “you didn’t scream, and i made it to the end of class with a flawless lecture. however…”

You shout as his phalanges roughly drag across your clit. An electric shock bursts through your entire body.

“…i never said i had to make you scream _during class_.”

You see stars – his magic dances on his fingertips and not a second passes after that until his cock’s girth becomes _so much more_. The stretch is almost too much at once. You’re vaguely aware that any sound you’ve made after that is basically one successive scream after the other, but with his magic practically vibrating your clit and his cock repeatedly slamming into you –

“ _SANS!_ ”

“that’s it, _scream_ my name!”

– an hour’s worth of in-class buildup draws into an orgasm that courses through your entire body. Your knees give out, forcing your hips to support yourself over the seat. A shock runs up your spine from the intensity and you try to quell your screaming.

Sans grunts harshly, his dick finally stopping deep inside you, releasing magic that fizzes and tingles within you. You barely notice – you’re still pulsing around his length, unable to come down from the post-bliss while you’re still being stretched like this.

Finally, his dick dissipates once more and you squeak when his thin hand taps your ass. “welp. looks like i really won after all.”

You groan, glaring over your shoulder. “We’ll see about that during the test, _Professor._ ”

 

**Author's Note:**

> welp it happened. 
> 
> apologies that it is relatively short -- of course, my first smut, it was a spur of the moment idea inspired by a post i saw from reawrite.tumblr but it was a while ago. so THX REAWRITE.TUMBLR.COM bc u made me a sinner.
> 
> uhhhh so this is my first officially posted smut ever so any feedback would be cool........ uhhHHHH DONT LOOK @ ME


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